I bought a new inexpensive speaker wire extension, and I get a loud hummm...
the new wire is "cloth-like", instead of the standard flexible plastic, [and they were inexpensive/cheap]
is it the cloth - or the "cheap" do you think, is the humming problem?
thanks marc
Neither. If the hum is due to the wire, then it's because it's unshielded and passes somewhere that it's picking up the noise, like adjacent to an AC line.
Bad ground somewhere. Probably made worse by close proximity to AC wiring, as trader4 pointed out, and perhaps also the wire is too small in diameter. What's the sound source and how is it powered, anyway?
is a cloth-type wire typically Unshielded?
[the old wire works fine, in the same spot, without humming]marc
it's a pair of stereo computer speakers, plugged into the back of the computer, with one light greenish plug [there is alot of wiring at the back of the computer]
I think I said, it works fine without using this new extension cord
I know I'm in an area I don't know much about
thanks, marc
Normally unshielded speaker wire will not cause hum. I'm thinking you have powered speakers of some sort. That's is to say the speaker is really a s peaker and an amplifier. If the speakers also have to have power such as a wall wart or regular cord plugged into an electrical outlet then you do ha ve powered speakers.
The cable you connect from your computer to powered speakers must be shield ed. Your new one is most likely not shielded. Replace it with a shielded one.
The description is not clear, but it sounds like he's talking about an AC extension cord for the wallwart that runs his computer speakers.
If so he might try reversing the plug. Or using a real power strip.
extension cord for the wallwart that runs his computer speakers.
Seems unlikely that any extension cord would cause hum. Just about all of those computer speakers use a wall wart that would be isolated from the mains.
Speaker wire is virtually all unsheilded. Perhaps the old cable is twisted and the new is not???
OK - you are talking POWERED speakers? The connection from the computer to the speakers is a low level signal, and any noise getting into the wire is amplified. You want sheilded cable for this -
extension cord for the wallwart that runs his computer speakers.
those computer speakers use a wall wart that would be isolated from the mains. A good number are straight AC powered - but I doubt he's talking about the power cord as he played the "shielded" card.
thanks all
the cable to the computer, the one I'm trying to extend, is the one causing the humm
a separate cord plugs into the wall, for power, and is away from the computer, and the other cable
marc
Twisting not needed for audio freqs. Everyone is just saying, without knowing the exact setup. I have not seen cloth cord used lately. Audio from computer can pickup common mode noise with long lines. Need isolation sometimes. Extension ????? Cloth reminds me of telephone.
Greg
e:
I kind of glossed over that, but you're right. Talk about lately, I don't know that I've seen it used in anything like this for decades. I don't know where you'd find wire for speakers that's cloth covered, or even just looks like it's cloth covered.
Twisted does wonders in reducing common mode interference but sheilded is better for the application. He needs a standard 1/8' stereo extention cable - and not a cheap headphone extention cable (which sounds like what he may have)
Neither.
Jenny Student at Olivet College of Design snipped-for-privacy@olivetuniversity.edu
That doesn't make sense. There was no hum before you added the "extension cable" so how can the one you're trying to extend be causing the problem?
It sounds to me like the the "extension" is causing the problem since is what as been added to the set up.
As a test, can you eliminate the original cable and just use the extension? If you get hum, it's that cable. If you don't, add the original back in and see what happens. If the hum comes back, try a different extension.
Obviously if the original is hard wired to the speakers, you can't do that.
Right now, you'd find cloth covered "speaker wire" on my dining room table.
My daughter has a pair of these headphones:
They have a 1 ft cord attached to the headphones with a 1/8 headphone jack and then a 3 ft 1/8" headphone plug/socket "extension" wire. Both of the cords are fabric covered as noted in the description.
My guess is that the OP has a similar "extension wire" for his computer speakers. I have a 20' 1/8" plug/socket extension wire for my computer speakers. The speakers sit on wall mounted shelves opposite the computer and facing out of the room so the sound carries farther.
Granted, my long extension is not fabric coded, but based on the one that came with my daughter's headphones, they do exist, at least in a 3 ft lengths.
Per this site, there may be an issue with static electricity and fabric covered headphone cords. I don't know (and doubt) that your issue is related to static electricity (i.e. hum vs. crackling) but I'll toss it out there anyway...
thanks Derby
marc
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